The present invention relates generally to the recovery and salvage of unmanned aircraft or other type of vehicles which upon descent are braked by means of a parachute and which, furthermore, upon impact on ground are cushioned in an appropriate manner.
Loads which are descending by means of a parachute should not impact upon ground without attenuation. Therefore, it has been proposed to provide such a load on its underside with annularly or toroidally shaped air cushions. Depending upon the material used for such a hose the cushion will be compressed to some extent upon impact. However, the inherent resiliency of such a structure will cause, in effect, the load to be propelled back, i.e. upwardly. In fact, the load may undergo a kind of oscillatory motion pursuant to which it will impact several times and be propelled back upwardly. Only after several such impact cycles it will come to rest.
Of course, it has to be considered that the load as it descends by means of a parachute, does not sink directly in vertical direction but depending, for example, on the wind and the initial throw speed the load has also a horizontal component of movement. This means that the load will meet the ground somewhat askew and the annulus is correspondingly irregularly deformed depending upon the composite motion and attitude of the load in the instant of impact. Moreover, the horizontal component of movement will cause the load to be dragged, to some extent, across the ground. This motion is not necessarily a stable, particularly in lateral direction with respect to the direction of horizontal movement, which means that the load may fall sideways and roll over.